The best computer is the fastest computer.
After all, since most of what you do is possible with any computer or smartphone, and any computer is simply a tool to get things done, the quicker you can get things done the better.
The whole idea with the computer is to get done faster, unless you have something which cannot be done with a fast computer, pretty unlikely.
Unless you need help, available really only from Apple, the latest Chromebooks and no contract smartphones will do the job cheaply.
To take advantage of a high speed computer, you also need a reliable and fast internet service.
There are two WiFi ways to connect. One is to a Internet provider via cable and wireless router . The other is to connect to a cell tower direct.
Cable service requires that everything be just right along the pipeline. Just having too many splitters between the service and your computer can drastically cut results.
Cell service does not have these problems. It has other problems.
The quality of cell tower service depends entirely, on how close you are to the cell tower signal. That can vary a lot, even over just a short distance.
Typically cell service is good in metro areas and not so good away from them. There is also a choice of slow 3G service or high speed 4G service.
4G service can be outstanding but it may or may not be available where you need it. In my experience cheaper 3G will handle most needs when traveling and away from home.
Yet I have found 4G service to be available at home at a reasonable cost. There is less waiting time to connect with with a website than with my cable service.
My Republic Wireless phone connects to the cheapest available service.
It took some considerable tinkering for my cable service to work as well as cell service even though it has the full potential to do so and exceed it except for waiting times to connect with websites.